Apparatus and method for regenerating a particulate filter of an exhaust system of an internal combustion engine

ABSTRACT

A power system has a fuel reformer, an emission abatement device, and a fuel cell. The fuel reformer reforms hydrocarbon fuels so as to produce a reformate gas which is supplied to both the emission abatement device and the fuel cell. A method of operating a fuel reformer so as to generate and supply a reformate gas to both an emission abatement device and a fuel cell is also disclosed.

This application is a continuation of U.S. patent application Ser. No.10/246,298 filed Sep. 18, 2002 which claims priority to U.S. ProvisionalPatent Application Ser. No. 60/351,580 filed on Jan. 25, 2002, theentirety of both of which is hereby incorporated by reference.

CROSS REFERENCE

Cross reference is made to U.S. patent application Ser. No. 10/418,808,filed Apr. 18, 2003, now abandoned, which claims priority to U.S.Provisional Patent Application Ser. No. 60/375,134 filed on Apr. 24,2002. Both of these applications name the same inventor as the presentapplication, and are assigned to the same assignee as the presentapplication. Similar claims to those presented herein were the subjectmatter of U.S. patent application Ser. No. 10/418,808.

Cross reference is also made to copending U.S. Utility patentapplication Ser. No. 10/245,921, filed Sep. 18, 2002 and Ser. No.10/246,118, filed Sep. 18, 2002, each of which is assigned to the sameassignee as the present application and is hereby incorporated byreference.

FIELD OF THE DISCLOSURE

The present disclosure relates to generally to a fuel reformer, and moreparticularly to an apparatus and method for operating a fuel reformer toprovide reformate gas to both a fuel cell and an emission abatementdevice.

BACKGROUND OF THE DISCLOSURE

A fuel reformer is operated to reform a hydrocarbon fuel into areformate gas. In the case of an onboard fuel reformer such as a fuelreformer associated with a vehicle or a stationary power generator, thereformate gas produced by the fuel reformer may be utilized as fuel orfuel additive in the operation of an internal combustion engine. Thereformate gas may also be utilized to regenerate or otherwise conditionan emission abatement device associated with an internal combustionengine or as a fuel for a fuel cell.

SUMMARY OF THE DISCLOSURE

According to one illustrative embodiment, there is provided a powersystem having a fuel reformer, an emission abatement device, and a fuelcell. The fuel reformer reforms hydrocarbon fuels so as to produce areformate gas which is supplied to both the emission abatement deviceand the fuel cell.

According to a more specific illustrative embodiment, there is provideda vehicle system of an on-highway truck having a fuel reformerconfigured to reform hydrocarbon fuel into a reformate gas, an emissionabatement device for treating the emissions from an internal combustionengine, and a fuel cell for generating electrical power. The reformategas from the fuel reformer is supplied to both the emission abatementdevice and the fuel cell. In such a way, the reformate gas may beutilized to regenerate or otherwise condition the emission abatementdevice during operation of the engine, while also being utilized tooperate the fuel cell during inoperation of the engine. Electrical powerfrom the fuel cell may be used to power an electrically-powered cabheating and cooling assembly with the need to idle the engine.

According to another illustrative embodiment, a single fuel reformer isutilized to regenerate or otherwise condition a combination emissionabatement assembly having a number of different devices for treating anumber of different exhaust effluents from the exhaust gas of aninternal combustion engine.

According to a more specific illustrative embodiment, the combinationemission abatement assembly has a NO_(X) trap and a soot particulatefilter. In such a case, the reformate gas from the fuel reformer is usedto selectively regenerate both the NO_(X) trap and the soot particulatefilter.

According to another illustrative embodiment, a fuel reformer isoperated in different modes of operation to generate and supplydifferent quantities and/or compositions of reformate gas to differentcomponents.

According to a more specific exemplary embodiment, the fuel reformer isoperated in one mode of operation to generate and supply a particularquantity and/or composition of reformate gas to a NO_(X) trap, and thenis operated in a different mode of operation to generate and supply anddifferent quantity and/or composition of reformate gas to a sootparticulate filter. In a similar manner, the fuel reformer is operatedin one mode of operation to generate and supply a particular quantityand/or composition of reformate gas to a fuel cell, and then is operatedin a different mode of operation to generate and supply and differentquantity and/or composition of reformate gas to an emission abatementdevice.

The above and other features of the present disclosure will becomeapparent from the following description and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of a fuel reforming assembly havinga plasma fuel reformer under the control of an electronic control unit;

FIG. 2 is a diagrammatic cross sectional view of the plasma fuelreformer of FIG. 1;

FIG. 3 is a simplified block diagram of a power system;

FIG. 4 is a simplified block diagram of the power system of FIG. 3 asused in the construction of a vehicle;

FIG. 5 is a simplified block diagram of another embodiment of a powersystem;

FIG. 6 is a simplified block diagram of the power system of FIG. 5 asused in the construction of a vehicle;

FIG. 7 is a diagrammatic cross sectional view of a soot particulatefilter that may be utilized in the construction of the power systems ofFIGS. 3-6;

FIG. 8 is a simplified block diagram of a combination emission abatementassembly;

FIG. 9 is a diagrammatic cross sectional view of the combinationemission abatement assembly of FIG. 8;

FIG. 10 is a simplified block diagram of a system having a pair of thecombination emission abatement assemblies of FIG. 9 positioned in aparallel arrangement; and

FIG. 11 is view similar to FIG. 10, but showing a system which has apair of plasma fuel reformers.

DETAILED DESCRIPTION OF THE DRAWINGS

As will herein be described in more detail, a fuel reformer, accordingto the concepts of the present disclosure, may be utilized to generateand supply a reformate gas to both a fuel cell and an emission abatementdevice. In such a way, the fuel reformer may be used to sustainoperation of the fuel cell, while also regenerating or otherwiseconditioning the emission abatement device. In the case of when the fuelreformer is a component of a vehicle system (e.g., an on-highway truck)or a stationary power generator, the fuel reformer allows for thetreatment of exhaust gases from the internal combustion engine of thevehicle or power generator during operation of the engine, while alsoallowing for the production of electrical power by the fuel cell duringinoperation of the engine (i.e., when the engine is not running).

A fuel reformer, according to further concepts of the presentdisclosure, may also be utilized to regenerate or otherwise condition acombination emission abatement assembly having a number of differentdevices for treating a number of different exhaust effluents from theexhaust gas of an internal combustion engine. For example, the fuelreformer is operated to generate and supply a reformate gas to anemission abatement assembly having a NO_(X) trap and a soot particulatefilter. In such a case, the reformate gas from the fuel reformer is usedto selectively regenerate both the NO_(X) trap and the soot particulatefilter.

A fuel reformer, according to additional concepts of the presentdisclosure, may be operated in different modes of operation to generateand supply different quantities and/or compositions of reformate gas todifferent components. For example, in the case of when the fuel reformeris operated to generate and supply reformate gas to both a NO_(X) trapand a particulate filter, the fuel reformer may be operated in one modeof operation to generate and supply a particular quantity and/orcomposition of reformate gas to the NO_(X) trap, and then be operated ina different mode of operation to generate and supply a differentquantity and/or composition of reformate gas to the particulate filter.A similar control scheme may also be utilized in the case of use of thefuel reformer to generate and supply reformate gas to both a fuel celland an emission abatement device. In particular, the fuel reformer maybe operated in one mode of operation to generate and supply a particularquantity and/or composition of reformate gas to the fuel cell, and thenbe operated in a different mode of operation to generate and supply adifferent quantity and/or composition of reformate gas to the emissionabatement device.

The fuel reformer described herein may be embodied as any type of fuelreformer such as, for example, a catalytic fuel reformer, a thermal fuelreformer, a steam fuel reformer, or any other type of partial oxidationfuel reformer. The fuel reformer of the present disclosure may also beembodied as a plasma fuel reformer. A plasma fuel reformer uses plasmato convert a mixture of air and hydrocarbon fuel into a reformate gaswhich is rich in, amongst other things, hydrogen gas and carbonmonoxide. Systems including plasma fuel reformers are disclosed in U.S.Pat. No. 5,425,332 issued to Rabinovich et al.; U.S. Pat. No. 5,437,250issued to Rabinovich et al.; U.S. Pat. No. 5,409,784 issued to Bromberget al.; and U.S. Pat. No. 5,887,554 issued to Cohn, et al., thedisclosures of each of which is hereby incorporated by reference.

For purposes of the following description, the concepts of the presentdisclosure will herein be described in regard to a plasma fuel reformer.However, as described above, the fuel reformer of the present disclosuremay be embodied as any type of fuel reformer, and the claims attachedhereto should not be interpreted to be limited to any particular type offuel reformer unless expressly defined therein.

Referring now to FIGS. 1 and 2, there is shown an exemplary embodimentof a plasma fuel reforming assembly 10 having a plasma fuel reformer 12and a control unit 16. The plasma fuel reformer 12 reforms (i.e.,converts) hydrocarbon fuels into a reformate gas that includes, amongstother things, hydrogen and carbon monoxide. As such, the plasma fuelreformer 12, as described further herein, may be used in theconstruction of an onboard fuel reforming system of a vehicle or astationary power generator. In such a way, the reformate gas produced bythe onboard plasma fuel reformer 12 may be utilized as fuel or fueladditive in the operation of an internal combustion engine therebyincreasing the efficiency of the engine while also reducing emissionsproduced by the engine. The reformate gas produced by the onboard plasmafuel reformer 12 may also be utilized to regenerate or otherwisecondition an emission abatement device associated with the internalcombustion engine. In addition, if the vehicle or the stationary powergenerator is equipped with a fuel cell such as, for example, anauxiliary power unit (APU), the reformate gas from the onboard plasmafuel reformer 12 may also be used as a fuel for the fuel cell.

As shown in FIG. 2, the plasma fuel reformer 12 includes aplasma-generating assembly 42 and a reactor 44. The reactor 44 includesa reactor housing 48 having a reaction chamber 50 defined therein. Theplasma-generating assembly 42 is secured to an upper portion of thereactor housing 48. The plasma-generating assembly 42 includes an upperelectrode 54 and a lower electrode 56. The electrodes 54, 56 are spacedapart from one another so as to define an electrode gap 58 therebetween.An insulator 60 electrically insulates the electrodes from one another.

The electrodes 54, 56 are electrically coupled to an electrical powersupply 36 (see FIG. 1) such that, when energized, an electrical currentis supplied to one of the electrodes thereby generating a plasma arc 62across the electrode gap 58 (i.e., between the electrodes 54, 56). Afuel input mechanism such as a fuel injector 38 injects a hydrocarbonfuel 64 into the plasma arc 62. The fuel injector 38 may be any type offuel injection mechanism which injects a desired amount of fuel intoplasma-generating assembly 42. In certain configurations, it may bedesirable to atomize the fuel prior to, or during, injection of the fuelinto the plasma-generating assembly 42. Such fuel injector assemblies(i.e., injectors which atomize the fuel) are commercially available.

As shown in FIG. 2, the plasma-generating assembly 42 has an annular airchamber 72. Pressurized air is advanced into the air chamber 72 throughan air inlet 74 and is thereafter directed radially inwardly through theelectrode gap 58 so as to “bend” the plasma arc 62 inwardly. Suchbending of the plasma arc 62 ensures that the injected fuel 64 isdirected through the plasma arc 62. Such bending of the plasma arc 62also reduces erosion of the electrodes 56, 58. Moreover, advancement ofair into the electrode gap 58 also produces a desired mixture of air andfuel (“air/fuel mixture”). In particular, the plasma reformer 12 reformsor otherwise processes the fuel in the form of a mixture of air andfuel. The air-to-fuel ratio of the air/fuel mixture being reformed bythe fuel reformer is controlled via control of the fuel injector 38 andan air inlet valve 40. The air inlet valve 40 may be embodied as anytype of electronically-controlled air valve. The air inlet valve 40 maybe embodied as a discrete device, as shown in FIG. 2, or may beintegrated into the design of the plasma fuel reformer 12. In eithercase, the air inlet valve 40 controls the amount of air that isintroduced into the plasma-generating assembly 42 thereby controllingthe air-to-fuel ratio of the air/fuel mixture being processed by theplasma fuel reformer 12.

The lower electrode 56 extends downwardly into the reactor housing 48.As such, gas (either reformed or partially reformed) exiting the plasmaarc 62 is advanced into the reaction chamber 50. A catalyst 78 may bepositioned in the reaction chamber 50. The catalyst 78 completes thefuel reforming process, or otherwise treats the gas, prior to exit ofthe reformate gas through a gas outlet 76. In particular, some or all ofthe gas exiting the plasma-generating assembly 42 may only be partiallyreformed, and the catalyst 78 is configured to complete the reformingprocess (i.e., catalyze a reaction which completes the reforming processof the partially reformed gas exiting the plasma-generating assembly42). The catalyst 78 may be embodied as any type of catalyst that isconfigured to catalyze such reactions. In one exemplary embodiment, thecatalyst 78 is embodied as substrate having a precious metal or othertype of catalytic material disposed thereon. Such a substrate may beconstructed of ceramic, metal, or other suitable material. The catalyticmaterial may be, for example, embodied as platinum, rhodium, palladium,including combinations thereof, along with any other similar catalyticmaterials. As shall be discussed below in greater detail, the plasmafuel reformer 12 may be embodied without the catalyst 78.

As shown in FIG. 2, the plasma fuel reformer 12 has a temperature sensor34 associated therewith. The temperature sensor 34 is used as a feedbackmechanism to determine the temperature of a desired structure of theplasma fuel reformer 12 or the gas advancing therethrough. For example,the temperature sensor 34 may be used to measure the temperature of thereformate gas being produced by the plasma fuel reformer 12, the ambienttemperature within the reaction chamber 50, the temperature of thecatalyst 78, etcetera. The temperature sensor 34 may be located in anynumber of locations. In particular, as shown in solid lines, thetemperature sensor 34 may be positioned within the reaction chamber 50at location in operative contact with the a structure (e.g., thecatalyst 78 or the walls of the reaction chamber 50) or a substance(e.g., the gas in the reaction chamber 50). To do so, the temperaturesensor 34 may be positioned in physical contact with the structure orsubstance, or may be positioned a predetermined distance away from thestructure or out of the flow of the substance, depending on the type andconfiguration of the temperature sensor.

Alternatively, the temperature of the desired structure or substance maybe determined indirectly. In particular, as shown in phantom, thetemperature sensor 34 may be positioned so as to sense the temperatureof the reformate gas advancing through the reaction chamber 50 or a gasconduit 80 subsequent to being exhausted through the outlet 76. Such atemperature reading may be utilized to calculate the temperature ofanother structure such as, for example, the catalyst 78 or the reactorhousing 48. Conversely, the temperature sensor 34 may be positioned tosense the temperature of the reactor housing 48 with such a temperaturereading then being correlated to the temperature of the reformate gas.In any such case, an indirect temperature sensed by the temperaturesensor 34 may be correlated to a desired temperature.

As shown in FIG. 1, the plasma fuel reformer 12 and its associatedcomponents are under the control of the control unit 16. In particular,the temperature sensor 34 is electrically coupled to the electroniccontrol unit 16 via a signal line 18, the fuel injector 38 iselectrically coupled to the electronic control unit 16 via a signal line20, the air inlet valve 40 is electrically coupled to the electroniccontrol unit 16 via a signal line 22, and the power supply 36 iselectrically coupled to the electronic control unit 16 via a signal line24. Moreover, as will herein be described in greater detail, a number ofother components associated with the plasma fuel reformer 12 may also beunder the control of the control unit 16, and, as a result, electricallycoupled thereto. For example, a flow diverter valve for selectivelydiverting a flow of reformate gas from the plasma fuel reformer 12between any number of components may be under the control of the controlunit 16. Similarly, a flow diverter valve for selectively diverting aflow of exhaust gas from an internal combustion engine between anynumber of components may also be under the control of the control unit16.

Although the signal lines 18, 20, 22, 24 (and any of the signal linesused to couple other devices to the control unit) are shownschematically as a single line, it should be appreciated that the signallines may be configured as any type of signal carrying assembly whichallows for the transmission of electrical signals in either one or bothdirections between the electronic control unit 16 and the correspondingcomponent. For example, any one or more of the signal lines 18, 20, 22,24 (or any other signal line disclosed herein) may be embodied as awiring harness having a number of signal lines which transmit electricalsignals between the electronic control unit 16 and the correspondingcomponent. It should be appreciated that any number of other wiringconfigurations may also be used. For example, individual signal wiresmay be used, or a system utilizing a signal multiplexer may be used forthe design of any one or more of the signal lines 18, 20, 22, 24 (or anyother signal line). Moreover, the signal lines 18, 20, 22, 24 may beintegrated such that a single harness or system is utilized toelectrically couple some or all of the components associated with theplasma fuel reformer 12 to the electronic control unit 16.

The electronic control unit 16 is, in essence, the master computerresponsible for interpreting electrical signals sent by sensorsassociated with the plasma fuel reformer 12 and for activatingelectronically-controlled components associated with the plasma fuelreformer 12 in order to control the plasma fuel reformer 12, the flow ofreformate gas exiting therefrom, and, in some cases, an exhaust gas flowfrom an internal combustion engine. For example, the electronic controlunit 16 of the present disclosure is operable to, amongst many otherthings, determine the beginning and end of each injection cycle of fuelinto the plasma-generating assembly 42, calculate and control the amountand ratio of air and fuel to be introduced into the plasma-generatingassembly 42, determine the temperature of the reformer 12 or thereformate gas, determine the power level to supply to the plasma fuelreformer 12, determine which component (e.g., a NO_(X) trap, aparticulate filter, or a fuel cell) to supply the reformate gas to,determine the composition or quantity of reformate gas to be generatedand supplied to a particular component.

To do so, the electronic control unit 16 includes a number of electroniccomponents commonly associated with electronic units which are utilizedin the control of electromechanical systems. For example, the electroniccontrol unit 16 may include, amongst other components customarilyincluded in such devices, a processor such as a microprocessor 28 and amemory device 30 such as a programmable read-only memory device (“PROM”)including erasable PROM's (EPROM's or EEPROM's). The memory device 30 isconfigured to store, amongst other things, instructions in the form of,for example, a software routine (or routines) which, when executed bythe processor 28, allows the electronic control unit 16 to controloperation of the plasma fuel reformer 12.

The electronic control unit 16 also includes an analog interface circuit32. The analog interface circuit 32 converts the output signals from thevarious fuel reformer sensors (e.g., the temperature sensor 34) or othersensors associated with the components associated with the plasma fuelreformer 12 into a signal which is suitable for presentation to an inputof the microprocessor 28. In particular, the analog interface circuit32, by use of an analog-to-digital (A/D) converter (not shown) or thelike, converts the analog signals generated by the sensors into adigital signal for use by the microprocessor 28. It should beappreciated that the A/D converter may be embodied as a discrete deviceor number of devices, or may be integrated into the microprocessor 28.It should also be appreciated that if any one or more of the sensorsassociated with the plasma fuel reformer 12 generate a digital outputsignal, the analog interface circuit 32 may be bypassed.

Similarly, the analog interface circuit 32 converts signals from themicroprocessor 28 into an output signal which is suitable forpresentation to the electrically-controlled components associated withthe plasma fuel reformer 12 (e.g., the fuel injector 38, the air inletvalve 40, the power supply 36, or other system components such as a gasflow diverter valve or the like). In particular, the analog interfacecircuit 32, by use of a digital-to-analog (D/A) converter (not shown) orthe like, converts the digital signals generated by the microprocessor28 into analog signals for use by the electronically-controlledcomponents associated with the fuel reformer 12 such as the fuelinjector 38, the air inlet valve 40, or the power supply 36. It shouldbe appreciated that, similar to the A/D converter described above, theD/A converter may be embodied as a discrete device or number of devices,or may be integrated into the microprocessor 28. It should also beappreciated that if any one or more of the electronically-controlledcomponents associated with the plasma fuel reformer 12 operate on adigital input signal, the analog interface circuit 32 may be bypassed.

Hence, the electronic control unit 16 may be operated to controloperation of the plasma fuel reformer 12 and components associatedtherewith. In particular, the electronic control unit 16 executes aroutine including, amongst other things, a closed-loop control scheme inwhich the electronic control unit 16 monitors the outputs from a numberof sensors in order to control the inputs to theelectronically-controlled components associated therewith. To do so, theelectronic control unit 16 communicates with the sensors associated withthe fuel reformer and the system in which it is being utilized in orderto determine, amongst numerous other things, the amount, temperature,and/or pressure of air and/or fuel being supplied to the plasma fuelreformer 12, the amount of hydrogen and/or oxygen in the reformate gas,the temperature of the reformer or the reformate gas, the composition ofthe reformate gas, the saturation level of an emission abatement device(e.g., a NO_(X) trap or particulate filter), etcetera. Armed with thisdata, the electronic control unit 16 performs numerous calculations eachsecond, including looking up values in preprogrammed tables, in order toexecute algorithms to perform such functions as determining when or howlong the fuel reformer's fuel injector or other fuel input device isopened, controlling the power level input to the fuel reformer,controlling the amount of air advanced through air inlet valve,controlling the position of a flow diverter valve responsible fordirecting the flow of reformate gas or exhaust gas from one component tothe other, determining the quantity and/or composition of reformate gasto generate and deliver to a particular component, etcetera.

Referring now to FIG. 3, there is shown a power system 110 having aninternal combustion engine 112 such as a diesel engine, the fuelreformer system 10, a fuel cell 116, and an emission abatement device118. Hydrocarbon fuel from a fuel tank 120 is supplied to the plasmafuel reformer 12. The hydrocarbon fuel in the fuel tank 120 may be thesame hydrocarbon fuel being combusted by the engine 112 (e.g., gasolineor diesel fuel), or, alternatively, may be a type of hydrocarbon fuelwhich is distinct from the engine's fuel.

As described above, the plasma fuel reformer 12 of the fuel reformerassembly 10 reforms hydrocarbon fuel into a reformate gas such as gasrich in hydrogen and carbon monoxide. The reformate gas is then suppliedto a number of other components associated with the power system 110.For example, the plasma fuel reformer 12 may be used to supply reformategas to the fuel cell 116. Specifically, hydrocarbon fuel from the fueltank 120 may be reformed by the plasma fuel reformer 12 into a reformategas which is input into the fuel cell 116. The fuel cell 116 of thepower system 110 may be provided as any type of fuel cell. For example,the fuel cell 116 may be embodied as an alkaline fuel cell (AFC), aphosphoric acid fuel cell (PAFC), a proton exchange membrane fuel cell(PEMFC), a solid oxide fuel cell (SOFC), a molten carbonate fuel cell(MCFC), or any other type of fuel cell.

The fuel cell 116 processes the reformate gas from the plasma fuelreformer 12 to create electrical energy which is used in the operationof the power system 110 or other components. For example, electricalenergy generated by the fuel cell 116 may be consumed by componentsassociated with the power system. For instance, electrical energygenerated by the fuel cell 116 may be used for operation of a number ofelectrical accessories such as systems electronics or the like. Itshould appreciated that the fuel cell 116 may be operated in conjunctionwith one or more batteries (not shown) to store electrical energy priorto consumption by electrical components associated with the system.

The reformate gas may also be supplied to the emission abatement device118. In such a case, the hydrogen-rich gas may be used to regenerate achemical catalyst or absorber which remove certain effluents (e.g., HC,CO, NO_(X), SO_(X), and in the case of a diesel engine, carbon-basedparticulate or “soot”) from the exhaust gases emitted from the internalcombustion engine 112. Specifically, the emission abatement device 118may include one or more catalytic converters or similar devices toreburn or otherwise treat any unburned gases in the exhaust gases. Assuch, the emission abatement device 118 may include platinum, rhodium,palladium, or other similar materials which are catalysts for thechemical reaction needed to burn off or otherwise treat any unburnedhydrocarbons and carbon monoxide by turning them into water vapor,carbon dioxide and other less toxic gases. Reformate gas from the plasmafuel reformer 12 may be utilized to condition the catalyst or otherwisefacilitate such an abatement process.

The emission abatement device 118 may also include one or moreabsorbers, traps, filters, or similar devices for trapping and removingcompounds such as oxides of nitrogen (NO_(X)), oxides of sulfur(SO_(X)), and/or soot. As described in greater detail herein in regardto FIGS. 5 and 6, additional oxidation catalysts may be used inconjunction with the traps of the emission abatement device 118 tooxidize certain compounds being exhausted from the traps (e.g., H₂S).Reformate gas from the plasma fuel reformer 12 may be used to regeneratesuch absorbers, traps, and filters. In particular, absorbers, traps, andfilters undergo a regeneration process during operation thereof in whichthe compound trapped in the absorber, trap, or filter is purgedtherefrom. Reformate gas from the plasma fuel reformer 12 may besupplied to the absorber, trap, or filter in order to facilitate such aregeneration process.

A NO_(X) trap used in the construction of the emission abatement device118 may be any type of commercially available NO_(X) trap. In the caseof when engine 112 is embodied as a diesel engine, the NO_(X) trap isembodied as a lean NO_(X) trap so as to facilitate the trapping andremoval of NO_(X) in the lean conditions associated with diesel exhaustgases. Specific examples of NO_(X) traps which may be used in theconstruction of the emission abatement device 118 include, but are notlimited to, NO_(X) traps commercially available from, or NO_(X) trapsconstructed with materials commercially available from, EmeraChem, LLCof Knoxville, Tenn. (formerly known as Goal Line EnvironmentalTechnologies, LLC of Knoxville, Tenn.).

A soot particulate filter used in the construction of the emissionabatement device 118 may be any type of commercially availableparticulate filter. For example, the soot particulate filter may beembodied as any known exhaust particulate filter such as a “deep bed” or“wall flow” filter. Deep bed filters may be embodied as metallic meshfilters, metallic or ceramic foam filters, ceramic fiber mesh filters,and the like. Wall flow filters, on the other hand, may be embodied as acordierite or silicon carbide ceramic filter with alternating channelsplugged at the front and rear of the filter thereby forcing the gasadvancing therethrough into one channel, through the walls, and outanother channel. Moreover, the soot particulate filter may also beimpregnated with a catalytic material such as, for example, a preciousmetal catalytic material.

The soot particulate filter for use as the emission abatement device 118may also be embodied as any of the devices described in copending,commonly assigned U.S. Provisional Patent Application Ser. No.60/375,134 entitled “Apparatus and Method for Regenerating a ParticulateFilter of an Exhaust System of an Internal Combustion Engine” filed onApr. 24, 2002 by Rudolf M. Smaling, the entirety of which is herebyincorporated by reference. As shown in FIG. 7, one exemplary emissionabatement device 300 constructed according to the teachings of theabove-incorporated provisional patent application, may be configured asa particulate filter assembly 302 having a catalyst 304 and a sootparticulate filter 306 positioned downstream from catalyst 304. Thecatalyst 304 may be spaced apart from the soot filter 306 by apredetermined distance (as shown in FIG. 7), may be positioned incontact with the soot particulate filter 306, or may even be fabricatedas a common structure with the soot particulate filter 306 (e.g., acommon structure having a catalyst portion positioned upstream of afilter portion).

The catalyst 304 may be embodied as any type of catalyst that isconfigured to catalyze the herein described reactions. In one exemplaryembodiment, the catalyst 304 is embodied as substrate having a preciousmetal or other type of catalytic material disposed thereon. Such asubstrate may be constructed of ceramic, metal, or other suitablematerial. The catalytic material may be, for example, embodied asplatinum, rhodium, palladium, including combinations thereof, along withany other similar catalytic materials.

The soot particulate filter 306, on the other hand, traps soot or otherparticulates present in the untreated exhaust gases from the engine 112.The soot particulate filter 306 may be embodied as any known exhaustparticulate filter such as the “deep bed” or “wall flow” filtersdescribed above. Similarly to as described above, the soot particulatefilter 306 may also be impregnated with a catalytic material such as,for example, a precious metal catalytic material.

During a regeneration cycle, reformate gas from the plasma fuel reformer12 is advanced into contact with the catalyst 304 to catalyze anoxidation reaction between the oxygen in the exhaust gas of the engine112 and the reformate gas. Specifically, when the reformate gas isadvanced into contact with the catalyst 304 in the presence of exhaustgas, the catalyst 304 catalyzes an oxidation reaction which converts thehydrogen gas present in the reformate gas and the oxygen present in theexhaust gases into, amongst other things, water. Moreover, the catalystcatalyzes an oxidation reaction which converts the carbon monoxidepresent in the reformate gas and the oxygen present in the exhaust gasesinto carbon dioxide.

Both of these oxidation reactions are highly exothermic, and, as aresult, produce heat that is transferred to the downstream-positionedsoot particulate filter 306. The heat, which may illustratively be inthe range of 600-650 degrees Celsius, ignites and burns soot particlestrapped in the particulate filter 306 thereby regenerating the filter306. It should be appreciated that such regeneration of the soot filter306 may be self-sustaining once initiated by heat from the exothermicreaction catalyzed by the oxidation catalyst 304. Specifically, once thesoot filter 306 is heated to a temperature at which the soot particlestrapped therein begin to ignite, the ignition of an initial portion ofsoot particles trapped therein can cause the ignition of the remainingsoot particles much in the same way a cigar slowly burns from one end tothe other. In essence, as the soot particles “burn”, an amount of heatis released in the “burn zone”. Locally, the soot layer (in the burnzone) is now much hotter than the immediate surroundings. As such, heatis transferred to the as yet un-ignited soot layer downstream of theburn zone. The energy transferred may be sufficient to initiateoxidation reactions that raise the un-ignited soot to a temperatureabove its ignition temperature. As a result of this, heat from theoxidation catalyst 304 may only be required to commence the regenerationprocess of the soot filter 306 (i.e., begin the ignition process of thesoot particles trapped therein).

In an illustrative embodiment, the soot filter 306 may have a catalyticmaterial such as, for example, a precious metal catalytic material,disposed on the surfaces thereof. The amount of catalytic materialdisposed on the filter 306 may be varied to fit the needs of a givensystem design. In one illustrative implementation, the soot filter 306may only use about 3% of the amount of catalytic material (e.g.,precious metals) which are present on a typical oxidation catalyst. Insuch a configuration (i.e., use of a catalyzed filter 306), the ignitiontemperature of the soot particles trapped in the filter 306 is reduced.Indeed, depending on, amongst other things, the amount of catalyticmaterial disposed on the filter 306 and the amount of accumulated sootparticles, the ignition temperature of the soot particles may be loweredto an ignition temperature of between 300-600 degrees Celsius. In otherexemplary implementations, the soot ignition temperature may be loweredto a temperature in the range of 300-550 degrees Celsius, moreparticularly in the range of 300-450 degrees Celsius, and even moreparticularly in the range of 300-350 degrees Celsius.

It should be appreciated that in addition to the aforedescribed use ofthe oxidation catalyst 304 to regenerate the soot filter 306, theoxidation catalyst 304 may also function as an oxidation catalyst forremoving certain compounds from the exhaust gases of the engine 112. Inparticular, the oxidation catalyst 304 may be configured to catalyze, inthe presence of heat supplied by the exhaust gasses (e.g., 250 degreesCelsius), an oxidation reaction which converts, for example,hydrocarbons (HC) and carbon monoxide (CO) into water vapor, carbondioxide, and other less toxic gases. Hence, the emission abatementdevice 300 may be used to not only remove soot from the engine's exhaustgases, but also other compounds as well (e.g., HC, CO).

As with conventional aftertreatment configurations, such functionalityof an oxidation catalyst 304 cannot be achieved until the exhaust gasesproduced by the engine 112 become hot enough to heat the oxidationcatalyst 304 to its light off temperature (e.g., approximately 250degrees Celsius). Hence, during startup, emissions of such compounds canreach undesirable levels since compounds can pass untreated through theoxidation catalyst 304 prior to the catalyst 304 reaching its light offtemperature. However, hydrogen gas may be supplied to the oxidationcatalyst 304 during startup to instantaneously, or near instantaneously,light off the oxidation catalyst 304. Specifically, during startup ofthe engine 112, hydrogen gas may be advanced to the face of theoxidation catalyst 304 thereby quickly lighting off the catalyst 304 ina much shorter period of time than if the catalyst 304 had to be lightedoff by heat from the engine's exhaust gases passing therethrough. Suchinstantaneous, or near instantaneous, light off of the catalyst 304prevents the release of untreated compounds during engine startup thatthe catalyst 304 is otherwise designed to treat.

As described above, the oxidation catalyst 304 catalyzes an exothermicreaction between a gaseous component containing oxygen and hydrogen.Generally, exhaust gases from the internal combustion engine 112 mayfunction as the source of oxygen. In particular, suitable amounts ofoxygen for sustaining such an oxidation reaction exist in the exhaustgases of an internal combustion engine without the introduction ofadditional oxygen. However, to fit the needs of a given design orimplementation, supplemental oxygen may be introduced into the engine'sexhaust gases prior to advancement thereof into the emission abatementdevice 300. One way to do this is by use of an air inlet (not shown)positioned upstream of the oxidation catalyst 304 for introducing adesired amount of air into the engine's exhaust gases prior toadvancement thereof into contact with the oxidation catalyst 304.

As shown in FIGS. 8 and 9, the emission abatement device 118 may also beembodied as a combination emission abatement assembly 400 having devicesfor treating multiple different compounds present in the exhaust stream.In particular, as will herein be described in greater detail in regardto FIGS. 8 and 9, the combination emission abatement assembly 400 may beembodied to include both a NO_(X) trap and a soot particulate filterassembly for trapping and removing both NO_(X) and soot from theengine's exhaust gases. In such a case, regeneration of both devices isfacilitated by use of the plasma fuel reformer 12.

Referring now to FIG. 4, there is shown a specific exemplaryimplementation of the power system 110. Specifically, the power system110, as embodied in FIG. 4, is used in the design of a vehicle such asan on-highway truck 150. As such, the output of the engine 112 drives orotherwise mechanically powers a transmission 122 associated with thetruck 150.

In the exemplary embodiment shown in FIG. 4, the fuel cell 116 may beoperated to provide electrical power to a number of componentsassociated with the truck 150. For example, the fuel cell 116 may beoperated to provide electrical power to a heating and cooling system124. Specifically, the truck 150 may be equipped with anelectrically-powered heater 126 and/or air conditioning unit 128 whichare operated on electrical power generated by the fuel cell 116 to heatand cool a passenger compartment 130 (e.g., a cab) associated with thetruck 150.

Other vehicle components 132 associated with the truck 150 may also beoperated on electrical power generated by the fuel cell 116. Suchcomponents 132 may include the truck's exterior and interior lighting,accessories (e.g., radio), electronic control systems (e.g., enginecontrol module, brake control module, etcetera), engine devices (e.g.,fuel pump, fuel injector system, etcetera), or the like. It should alsobe appreciated that electrical power from the fuel cell 116 may also beused to operate the plasma fuel reformer 12, if need be.

As described herein, the fuel cell 116 may be configured to provideelectrical power to the entire truck 150 much in the same way power isprovided in a conventional truck design by an alternator (and associatedbatteries). However, in the case of use of the fuel cell 116 to provideelectrical power to the truck 150, the internal combustion engine 112does not have to be operated (i.e., the engine 112 does not need to berunning) in order to provide sustained amounts of electrical power inthe manner it would be if power were to be provided through aconventional alternator arrangement.

Reformate gas from the plasma fuel reformer 12 may be generated andsupplied to the emission abatement device 118 during operation of theengine 112. Specifically, during operation of the internal combustionengine 112, the electronic control unit 16 controls operation of theplasma fuel reformer 12 such that reformate gas is generated andsupplied to the emission abatement device 118 so as to selectivelyregenerate or otherwise treat the emission abatement device 118 duringoperation of the engine 112. However, during inoperation of the engine(i.e., during periods of time when the engine is not running), theelectronic control unit 16 controls operation of the plasma fuelreformer 12 such that reformate gas is generated and supplied to thefuel cell 116 so as to allow for the production of electrical energy bythe fuel cell 116. In such a case, mechanical output from the engine 112is riot necessary to provide sustained levels of power therebyfacilitating operation of electrical accessories (e.g., the heating andcooling system 124) without the need to idle or otherwise operate theengine 112.

An electronically-controlled flow diverter valve 136 is utilized toselectively direct the flow of reformate gas from the plasma fuelreformer 12 between the fuel cell 116 and emission abatement device 118.The diverter valve 136 is electrically coupled to the electronic controlunit 16 via a signal line 138. As such, the position of the divertervalve 136 is under the control of the electronic control unit 16. As aresult, the electronic control unit 16, amongst its other functions, mayselectively direct the flow of reformate gas from the plasma fuelreformer 12 to either the fuel cell 116 or the emission abatement device118.

It should be appreciated that in certain system configurations, the flowof reformate gas from the plasma fuel reformer 12 may be split by use ofthe flow diverter valve 136 with a portion of the reformate gas beingsupplied to the fuel cell 116 and another portion of the reformate gasbeing supplied to the emission abatement device 118. In particular, ifdesired, a portion of the reformate gas produced by the plasma fuelreformer 12 could also be supplied to the fuel cell 116 during operationof the engine 112. Specifically, the fuel cell 116 may be operated toprovide electrical power when the engine 112 is running in addition towhen the engine 112 is not running.

Referring now to FIG. 5, there is shown another exemplary embodiment ofa power system (hereinafter referred to with reference numeral 210). Thepower system 210 is somewhat similar to the power system 110 of FIGS. 3and 4. As such, the same reference numerals are used in FIGS. 5 and 6 todesignate common components which were previously discussed in regard toFIGS. 3 and 4, with additional discussion thereof being unwarranted.

As shown in FIG. 5, the emission abatement device 118 of the powersystem 210 is embodied as a pair of traps 232, 234. The traps 232, 234trap, store, or otherwise remove certain compounds from the engine'sexhaust gases such as NO_(X) and SO_(X). Once trapped, the compounds arethen exposed to a catalytic regeneration reaction which breaks thecompounds down into less harmful compounds prior to being exhausted.

A diverter valve 236 selectively diverts the flow of exhausts gases fromthe engine 112 between the traps 232, 234. For example, exhaust gasesfrom the engine 112 may be routed through the trap 232 while the trap234 is maintained “offline.” While offline, the trap 234 may undergoregeneration. Once the trap 234 has been regenerated, the position ofthe diverter valve 236 may be switched such that exhaust gases from theengine 112 are routed through the trap 234 while the trap 232 is offlinefor regeneration.

It should be appreciated that the exhaust gas diverter valve 236 may beembodied as either a two position valve, or, in some configurations, avariable flow valve. In the case of use of a two position valve, theflow of exhaust gases is completely interrupted to the offline trap 232,234. In other words, the offline trap 232, 234 is isolated from the flowof exhaust gases. However, in the case of use of a variable flow valve,a desired amount of the exhaust gas flow may be directed through theoffline trap 232, 234. This reduced flow may be utilized to facilitatethe regeneration process of the trap 232, 234 depending on the type anddesign of the trap 232, 234. For example, during regeneration of aNO_(X) trap, it may be desirable to have little to no flow of exhaustgases through the trap. However, in the case of regeneration of a sootparticulate filter such as the filter described in the aforementionedand incorporated U.S. Provisional Patent Application, it may bedesirable to have some degree of a flow of exhaust gases through filterduring regeneration thereof. For example, it may be desirable to put acontrolled flow of exhaust gas through the filter to supply sufficientamounts of oxygen to sustain the oxidation reactions at the face of theupstream catalyst (i.e., the catalyst which creates the heat to burn thesoot in the downstream filter) and to provide sufficient amounts ofoxygen to burn the soot in the soot filter with the heat generated bythe catalyst.

To operate in such a manner, the diverter valve 236 is electricallycoupled to the electronic control unit 16 via a signal line 238. Assuch, the position of the diverter valve 236 is under the control of theelectronic control unit 16. Hence, the electronic control unit 16,amongst its other functions, selectively directs the flow of exhaust gasfrom the engine 112 to either the trap 232 or the trap 234, or acombination of both traps 232, 234 in the case of a variable flowdiverter valve 236.

The control scheme for controlling the position of the diverter valve236 may be designed in a number of different manners. For example, atiming-based control scheme may be utilized in which the position of thediverter valve 236 is changed as a function of time. For instance,regeneration of the traps 232, 234 may be performed at predeterminedtimed intervals.

Alternatively, a sensor-based control scheme may be utilized. In such acase, the position of the diverter valve 236 is changed as a function ofoutput from one or more sensors associated with the traps 232, 236. Forinstance, regeneration of one of the traps 232, 234 may commence whenthe output from NO_(X) sensor(s) (not shown) associated with theparticular trap 232, 234 is indicative of a predetermined saturationlevel.

A flow diverter valve 246 is used to direct reformate gas from theplasma fuel reformer 12 to the appropriate trap 232, 234. In particular,the diverter valve 246 selectively diverts the flow of reformate gasbetween the traps 232, 234. For example, reformate gas from the plasmafuel reformer 12 is routed through the diverter valve 246 to the trap232 when the trap 232 is offline and undergoing a regeneration cycle.When it is time to regenerate the trap 234, the position of the divertervalve 246 may be switched such that reformate gas from the plasma fuelreformer 12 is routed through the diverter valve 246 to the trap 234when the trap 234 is offline for regeneration.

To operate in such a manner, the diverter valve 246 is electricallycoupled to the electronic control unit 16 via a signal line 248. Assuch, the position of the diverter valve 246 is under the control of theelectronic control unit 16. Hence, the electronic control unit 16,amongst its other functions, selectively directs the flow of reformategas from the plasma fuel reformer 12 to either the trap 232 or the trap234.

The control scheme executed by the control unit 16 controls the positionof the various diverter valves in order to selectively direct reformategas and exhaust gases to the appropriate trap 232, 234. In particular,the control unit 16 coordinates the position of the reformate gasdiverter valves 136 and 246 with the exhaust diverter valve 236 todirect the flow of reformate gas and exhaust gas to the appropriate trap232, 234. In particular, when the exhaust diverter valve 236 ispositioned so as to direct exhaust gas through the trap 232 (i.e., thetrap 234 is offline), the reformate gas diverter valves 136, 246 arerespectively positioned so as to direct the flow of reformate gas fromthe plasma fuel reformer 12 to the trap 234 thereby facilitatingregeneration thereof. Conversely, when the exhaust diverter valve 236 ispositioned so as to direct exhaust gas through the trap 234 (i.e., thetrap 232 is offline), the reformate gas diverter valves 136, 246 arerespectively positioned so as to direct the flow of reformate gas fromthe plasma fuel reformer 12 to the trap 232 thereby facilitatingregeneration thereof.

It should be appreciated that the emission abatement device 118 may beconfigured to include one or more additional catalysts to function inconjunction with the traps 232, 234. For example, an oxidation catalyst(not shown) may be positioned downstream from the traps 232, 234 tooxidize any H₂S that may be present in the gases being exhausted fromthe traps 232, 234.

The emission abatement device 118 of the power system 210 may also beconfigured to include one or more soot particulate filters such as thesoot particulate filters described above. In such a case, the sootparticulate filters may be arranged in a similar parallel configurationas the traps 232, 234, with one soot particulate filter being operatedto trap soot from the flow of exhaust gases while the other sootparticulate filter is offline for regeneration. Alternatively, ifdesired, the soot particulate filter may be housed in the same structureas the traps 232, 234. Use of a soot particulate filter is particularlyuseful in the case of when the internal combustion engine 112 isembodied as a diesel engine.

Referring now to FIG. 6, there is shown a specific exemplaryimplementation of the power system 210. Specifically, in a similarmanner to as described herein in regard to FIG. 4, the power system 210may be used in the design of a vehicle such as the on-highway truck 150.In such a case, the plasma fuel reformer 12 may be operated to providereformate gas to the truck's fuel cell 116 and the traps 232, 234 of theemission abatement device 118.

Similarly to as described herein in regard to FIG. 4, the fuel cell 116of the power system 210 may be operated to provide electrical power to anumber of components associated with the truck 150. For example, thefuel cell 116 may be operated to provide electrical power to theelectrically-powered heater 126 and/or air conditioning unit 128 of thetruck's heating and cooling system 124 thereby providing heated andcooled air to the cab 30 of the truck 150. Moreover, other vehiclecomponents 132 such as the truck's exterior and interior lighting,accessories (e.g., radio), electronic control systems (e.g., enginecontrol module, brake control module, etcetera), engine devices (e.g.,fuel pump, fuel injector system, etcetera), or the like may be poweredby electrical energy generated by the fuel cell 116 of the power system210. Electrical power from the fuel cell 116 may also be used to operatethe plasma fuel reformer 12. Specifically, as described herein, theplasma fuel reformer 12 requires electrical power to generate a plasmafield. Such electrical power may be provided by the fuel cell 116.

It should be appreciated that a power generation scheme may beimplemented to leverage mechanical output from the engine duringoperation thereof. For example, electrical power may be supplied to thetruck's electrical components (e.g., the heating and cooling system 124,the plasma fuel reformer 12, etcetera) by use of a conventional powergenerating system (e.g., an alternator) during operation of the engine112 with electrical energy from the fuel cell 116 being utilized topower the truck's electrical components during inoperation of the engine(i.e., when the engine 112 is not running).

The configurations of the power systems described herein may be variedto fit the needs of a given application. For example, the plasma fuelreformer 12 need not only be used in conjunction with the emissionabatement device 118 of FIGS. 5 and 6 (i.e., a device which includes thetraps 232, 234), but rather may be used in conjunction with any type ofemission abatement device. In a similar manner, the emission abatementdevice 118 of FIGS. 5 and 6 need not only be used in conjunction withthe plasma fuel reformer 12, but rather may be used in conjunction withany type of fuel reformer.

Moreover, the power systems described herein have numerous otherapplications. For example, the power systems described herein may beused in the design of a hybrid vehicle. In such a case, the mechanicaloutput from the internal combustion engine 112 may be mechanicallycoupled to a power generator which converts rotary mechanical power intoelectrical power which is stored in the hybrid vehicle's batteries foruse by the vehicle's electric motor.

The power systems described herein also have numerous applications otherthan vehicular power systems. For example, the power systems describedherein may be used in the design of a stationary power generatingsystem. In such a case, the mechanical output from the internalcombustion engine 112 may be mechanically coupled to a power generatorwhich converts rotary mechanical power into electrical power. Moreover,the mechanical output of the internal combustion engine 112 may be usedto drive a pump mechanism or the like associated with a pump assembly.

The configuration of the power systems described herein may also bemodified to provide reformate gas to other components associated withthe system in addition to the fuel cell and the emission abatementdevice. For example, reformate gas from the plasma fuel reformer may besupplied to the intake of the internal combustion engine. Indeed, aseither the sole fuel source, or as a fuel additive, the combustion ofreformate gas significantly reduces emissions during operation of theengine. This is particularly useful in the case of when the internalcombustion engine 112 is embodied as a spark-ignited engine whichcombusts a hydrocarbon fuel such as gasoline, natural gas, methanol, orpropane. In such a configuration (i.e., reformate gas is being suppliedto the intake of the engine prior to combustion), it may be possible toeliminate one or more emission abatement mechanisms from the powersystem as a result of the reduction in emissions produced by the engine.

To provide reformate gas to the internal combustion engine, the enginemay be configured to include a carburetor for advancing the reformategas into the engine's combustion chambers, a fuel injection assembly forinjecting the reformate gas into the engine's combustion chambers, orany other similar device depending on the particular design of theengine. Alternatively, the engine's existing fuel delivery system may bemodified to simultaneously inject or otherwise advance hydrocarbon fueland reformate gas into the engine's combustion chambers. The fuelreformer may be configured to fluidly communicate reformate gas to anysuch a mechanism associated with the engine.

Referring now to FIGS. 8 and 9, there is shown a combination emissionabatement assembly 400. The emission abatement assembly 400 may be usedas the emission abatement device 118 of the herein described powersystems 110, 210. However, the emission abatement assembly may also beutilized in the construction of many other systems including systemswhich may or may not include a fuel cell. The combination emissionabatement assembly 400 has a number of different devices for treating anumber of different exhaust effluents from the exhaust gas of aninternal combustion engine. For example, as will now be described ingreater detail, the plasma fuel reformer 12 may be operated to generateand supply a reformate gas to an emission abatement assembly having botha NO_(X) trap 402 and a soot particulate filter 404. In such a case, thereformate gas from the plasma fuel reformer 12 is used to selectivelyregenerate both the NO_(X) trap 402 and the soot particulate filter 404.

As shown in FIG. 9, the soot NO_(X) trap 402 and the soot particulatefilter 404 may be housed in separate housings coupled to one another byuse of, for example, sections of exhaust pipe. Alternatively, the NO_(X)trap 402 and the soot particulate filter 404 may be fabricated in acommon housing.

It should be appreciated that the components (i.e., the NO_(X) trap 402and the soot particulate filter 404) may be positioned in any order orarrangement to fit the needs of a give system. In particular, based on anumber of system design considerations, it may be desirable to positionone device upstream of the other, whereas in other system designs theopposite positioning may be more desirable. In the exemplary embodimentdescribed herein, the soot particulate filter 404 of the emissionabatement assembly 400 is positioned downstream from the NO_(X) trap402. As will be described herein, such an arrangement facilitatescontrol of both the NO_(X) trap regeneration process and the sootparticulate filter regeneration process.

As with the NO_(X) traps described above in regard to FIGS. 3-6, theNO_(X) trap 402 of the combination emission abatement assembly 400 maybe any type of commercially available NO_(X) trap. In the case of whenthe emission abatement assembly 400 is used to treat exhaust gases froma diesel engine, the NO_(X) trap 402 is embodied as a lean NO_(X) trapso as to facilitate the trapping and removal of NO_(X) in the leanconditions associated with diesel exhaust gases. Specific examples ofNO_(X) traps which may be used in the construction of the combinationemission abatement assembly include, but are not limited to, theaforementioned NO_(X) traps commercially available from, or NO_(X) trapsconstructed with materials commercially available from, EmeraChem.

The soot particulate filter used in the construction of the combinationemission abatement assembly 400 may be any type of commerciallyavailable particulate filter. For example, similar to as described abovein regard to the soot filters of FIGS. 3-6, the soot particulate filter404 may be embodied as any known exhaust particulate filter such as a“deep bed” or “wall flow” filter. Deep bed filters may be embodied asmetallic mesh filters, metallic or ceramic foam filters, ceramic fibermesh filters, and the like. Wall flow filters, on the other hand, may beembodied as a cordierite or silicon carbide ceramic filter withalternating channels plugged at the front and rear of the filter therebyforcing the gas advancing therethrough into one channel, through thewalls, and out another channel. Moreover, the soot particulate filter404 may also be impregnated with a catalytic material such as, forexample, a precious metal catalytic material. In the exemplaryembodiment described herein and shown in FIGS. 8 and 9, the sootparticulate filter 404 of the combination emission abatement assembly400 is embodied as one of the devices described in the aforementionedand incorporated U.S. Provisional Patent Application Ser. No.60/375,134.

Referring now to FIG. 9, the combination emission abatement assembly 400is shown in greater detail. The NO_(X) absorber catalyst 406 of theNO_(X) trap 402 is housed in an interior chamber 408 of a housing 410.The housing 410 has an upstream end 412 coupled to an exhaust pipe 414,and a downstream end 416 coupled to an exhaust pipe 418. The upstreamend 412 of the housing 410 defines an exhaust gas inlet 420, whereas thedownstream end 416 of the housing 410 defines an exhaust gas outlet 422.Hence, exhaust gases from the diesel engine enter the housing 410through the exhaust gas inlet 420, are advanced through the NO_(X)absorber catalyst 406, and then are exhausted from the housing 410 viathe exhaust gas outlet 422.

The NO_(X) trap 402 has an inlet 424 for receiving reformate gas fromthe plasma fuel reformer 12. The inlet 424 may be configured as anorifice that is defined in the walls of the housing 410, or,alternatively, may include a tube, coupling assembly, or other structurewhich extends through the wall of the housing 410. In addition, if thereformate gas is introduced upstream of the upstream end 412 of thehousing 410, the exhaust gas inlet 420 of the housing 410 functions asthe reformate gas inlet of the NO_(X) trap 402.

The plasma fuel reformer 12 is fluidly coupled to the reformate gasinlet associated with the NO_(X) trap 402. In particular, a first end ofa fluid line 426 is coupled to the outlet of the plasma fuel reformer 12(via a flow diverter valve 466, as described below), whereas a secondend of the fluid line 426 extends through, or is coupled to, the gasinlet 424 such that reformate gas may be advanced into the chamber 408of the housing 410. In such a manner, reformate gas from the plasma fuelreformer 12 may be advanced into contact with the NO_(X) absorbercatalyst 406.

As shown in FIGS. 8 and 9, the electronic control unit 16 is alsoelectrically coupled to a pair of NO_(X) sensors 428, 430 via a pair ofsignal lines 432, 434, respectively. The NO_(X) sensors 428, 430 areutilized to sense the difference in NO_(X) concentration across theNO_(X) absorber catalyst 406 in order to determine when the NO_(X) trap402 requires regeneration. In particular, the NO_(X) sensors 428, 430cooperate to determine the amount of NO_(X) being removed from theexhaust gases (i.e., trapped) by the NO_(X) absorber catalyst 406. Whenthe amount of NO_(X) being trapped by the NO_(X) absorber catalyst 406diminishes to a predetermined level, the electronic control unit 16commences the regeneration process. It should be appreciated that whileshown in FIGS. 8 and 9 as utilizing two NO_(X) sensors, a single NO_(X)sensor on the downstream side of NO_(X) absorber catalyst 406 may beutilized, if desired. In such a configuration, the electronic controlunit 16 would monitor when the NO_(X) concentration sensed by the singleNO_(X) sensor exceeded a predetermined upper threshold, as opposed tomonitoring the NO_(X) removal efficiency across the NO_(X) absorbercatalyst 406.

Alternatively, other control schemes may also be utilized to commence aregeneration cycle. For example, a timing-based control scheme may beutilized in which the NO_(X) trap 402 is regenerated as a function oftime. In such a case, regeneration of the NO_(X) trap 402 is performedat predetermined timed intervals.

Referring back to FIG. 9, the soot particulate filter 404 is also shownin greater detail. A catalyst 436 and a filter 438 of the sootparticulate filter 404 are housed in an interior chamber 440 of ahousing 442. The housing 442 has an upstream end 444 coupled to theexhaust pipe 418 extending from the downstream end 416 of the NO_(X)trap housing 410. The housing 442 also has a downstream end 446 coupledto an exhaust pipe 448 that is either open to the atmosphere or coupledto an additional exhaust system component (not shown) positioneddownstream of the combination emission abatement assembly 400. Theupstream end 444 of the housing 442 defines an exhaust gas inlet 450,whereas the downstream end 446 of the housing 442 defines an exhaust gasoutlet 452. Hence, exhaust gases from the engine enter the housing 442through the exhaust gas inlet 450, are advanced through the catalyst 436and the soot filter 438, and then are exhausted from the housing 442 viathe exhaust gas outlet 452.

The soot particulate filter 404 has an inlet 454 for receiving reformategas from the plasma fuel reformer 12. Similar to the inlet of the NO_(X)trap 402, the inlet of the soot particulate filter 404 may be configuredas an orifice that is defined in the walls of the housing 442, or,alternatively, may include a tube, coupling assembly, or other structurewhich extends through the wall of the housing 442. In addition, if thereformate gas is introduced upstream of the upstream end 444 of thehousing 442, the exhaust gas inlet 450 of the housing 442 functions asthe reformate gas inlet of the soot particulate filter 404.

The plasma fuel reformer 12 is fluidly coupled to the reformate gasinlet associated with the soot particulate filter 404. In particular, afirst end of a fluid line 456 is coupled to the outlet of the plasmafuel reformer 12 (via the flow diverter valve 466, as described below),whereas a second end of the fluid line 456 extends through, or iscoupled to, the gas inlet 454 such that reformate gas may be advancedinto the chamber 440 of the housing 442. In such a manner, the reformategas from the plasma fuel reformer 12 may be introduced into a flow ofexhaust gas from the engine and into contact with the catalyst 436. Inparticular, as described above in regard to FIG. 7, during aregeneration cycle, reformate gas from the plasma fuel reformer 12 isadvanced into contact with the catalyst 436 to catalyze an oxidationreaction between the oxygen in the exhaust gas of the engine and thereformate gas. Specifically, when the reformate gas is advanced intocontact with the catalyst 436 in the presence of exhaust gas (or othersource of oxygen), the catalyst 436 catalyzes an oxidation reactionwhich converts the hydrogen gas present in the reformate gas and theoxygen present in the exhaust gases into, amongst other things, water.Moreover, the catalyst 436 catalyzes an oxidation reaction whichconverts the carbon monoxide present in the reformate gas and the oxygenpresent in the exhaust gases into carbon dioxide. Both of theseoxidation reactions are highly exothermic, and, as a result, produceheat that is transferred to the downstream-positioned soot filter 438.The heat, which may illustratively be in the range of 600-650 degreesCelsius, ignites and burns soot particles trapped in the soot filter 438thereby regenerating the soot particulate filter 404.

As shown in FIGS. 8 and 9, the electronic control unit 16 is alsoelectrically coupled to a pair of pressure sensors 458, 460 via a pairof signal line 462, 464, respectively. The pressure sensors 458, 460 maybe utilized to sense the pressure difference across the soot particulatefilter 404 in order to determine when the soot filter 438 requiresregeneration. Specifically, when the pressure drop across the sootparticulate filter 404 increases to a predetermined value, theelectronic control unit 16 commences the filter regeneration process. Itshould be appreciated that while shown in FIGS. 8 and 9 as utilizing twopressure sensors, a single pressure sensor on either side of sootparticulate filter 404 may be utilized, if desired. In such aconfiguration, the electronic control unit 16 would monitor when thepressure sensed by the single pressure sensor exceeded a predeterminedupper threshold or was below a predetermined lower threshold, as opposedto monitoring the pressure drop across the soot particulate filter 404.

As alluded to above, an electronically-controlled flow diverter valve466 is utilized to selectively direct the flow of reformate gas from theplasma fuel reformer 12 between the NO_(X) trap 402 and the sootparticulate filter 404. In particular, one end of a fluid line 480 iscoupled to the outlet 76 of the plasma fuel reformer, whereas the otherend of the fluid line 480 is coupled to the inlet of the diverter valve466. A first outlet of the diverter valve 466 is fluidly coupled to theinlet 424 of the NO_(X) trap 402 via the fluid line 426, whereas asecond outlet of the diverter valve 466 is fluidly coupled to the inlet454 of soot particulate filter 404 via the fluid line 456.

The diverter valve 466 is electrically coupled to the electronic controlunit 16 via a signal line 468. As such, the position of the divertervalve 466 is under the control of the electronic control unit 16. As aresult, the electronic control unit 16, amongst its other functions,selectively directs the flow of reformate gas from the plasma fuelreformer 12 to either the NO_(X) trap 402 or the soot particulate filter404. Hence, during operation of the engine, the electronic control unit16 executes a control routine that, amongst other things, determineswhen to regenerate the respective components of the combination emissionabatement assembly 400. In particular, based on the type of controlscheme being utilized (e.g., a sensor-based control scheme or atime-based control scheme), the electronic control unit 16 determineswhen to regenerate the NO_(X) trap 402 and the soot particulate filter404 and thereafter positions the diverter valve 466 in a desiredposition so as to direct the flow of reformate gas from the plasma fuelreformer 12 to the appropriate device (i.e., to either the NO_(X) trap402 or the soot particulate filter 404). It should be appreciated thatin certain system configurations, the flow of reformate gas from theplasma fuel reformer 12 may be split by use of the flow diverter valve466 with a portion of the reformate gas being supplied to the NO_(X)trap 402 and another portion of the reformate gas being supplied to thesoot particulate filter 404.

Referring now to FIG. 10, there is shown an exhaust gas treatment systemwhich utilizes a pair of the emission abatement assemblies 400positioned in a parallel arrangement similar in nature to the traps 232,234 of FIGS. 5 and 6. The same reference numerals are used in FIG. 10 todesignate common components which were previously discussed in regard toFIGS. 8 and 9 with additional discussion thereof being unwarranted.Moreover, a number of components from FIGS. 8 and 9 (e.g., the signallines associated with the sensors) have been removed for clarity ofdescription.

As shown in FIG. 10, an exhaust gas diverter valve 470 selectivelydiverts the flow of exhausts gases between the two combination emissionabatement assemblies 400. For example, exhaust gases from the engine 112may be routed through one of the assemblies 400 while the other assembly400 is maintained offline. While offline, one or both of the NO_(X) trap402 and the soot particulate filter 404 of the assembly 400 may undergoregeneration. Once the NO_(X) trap 402 and/or the soot particulatefilter 404 have been regenerated, the position of the diverter valve 470may be switched such that exhaust gases from the engine are routedthrough the recently regenerated emission abatement assembly 400 whilethe other assembly 400 is offline for regeneration.

It should be appreciated that the exhaust gas diverter valve 470 may beembodied as either a two position valve, or, in some configurations, avariable flow valve. In the case of use of a two position valve, theflow of exhaust gases is completely interrupted to the offlinecombination emission abatement system 400. In other words, the offlinecombination emission abatement assembly 400 is isolated from the flow ofexhaust gases. However, in the case of use of a variable flow valve, adesired amount of the exhaust gas flow may be directed through theoffline combination emission abatement assembly 400. This reduced flowmay be utilized to facilitate the regeneration process of one or both ofthe NO_(X) trap 402 and the soot particulate filter 404. For example,during regeneration of the NO_(X) trap 402, it may be desirable to havelittle to no flow of exhaust gases through the trap. However, in thecase of regeneration of the soot particulate filter 404, it may bedesirable to have some degree of a flow of exhaust gases through filter404. For example, it may be desirable to advance a controlled flow ofexhaust gas through the filter 404 to supply sufficient amounts ofoxygen to sustain the oxidation reactions at the face of the upstreamcatalyst 436 and to provide sufficient amounts of oxygen to burn thesoot in the soot filter 438 with the heat generated by the catalyst 436.

To operate in such a manner, the diverter valve 470 is electricallycoupled to the electronic control unit 16 via a signal line 472. Assuch, the position of the diverter valve 470 is under the control of theelectronic control unit 16. Hence, the electronic control unit 16,amongst its other functions, selectively directs the flow of exhaust gasfrom the engine, or a portion of the flow of exhaust gas from theengine, to the appropriate combination emission abatement assemblies400.

The control scheme for controlling the position of the diverter valve470 may be designed in a number of different manners. For example, atiming-based control scheme may be utilized in which the position of thediverter valve 470 is changed as a function of time. For instance,regeneration of the individual devices of the combination emissionabatement assemblies 400 may be performed at predetermined timedintervals.

Alternatively, as described above, a sensor-based control scheme may beutilized to detect when a particular NO_(X) trap 402 or a particularsoot particulate filter 404 of the assemblies 400 is in need ofregeneration. In such a case, the position of the diverter valve 470 ischanged as a function of the output from one or more sensors associatedwith the assemblies 400. For instance, regeneration of one of the NO_(X)traps 402 may commence when the output from the NO_(X) sensors 428, 430associated with the particular trap 402 is indicative of a predeterminedsaturation level. Similarly, regeneration of one of the soot particulatefilters 404 may commence when output from the pressure sensors 458, 460associated with the particular soot particulate filter 404 is indicativeof a predetermined saturation level.

A flow diverter valve 474 is used to direct reformate gas from theplasma fuel reformer 12 to the appropriate emission abatement assembly400. In other words, the diverter valve 474 selectively diverts the flowof reformate gas between the two emission abatement assemblies 400. Forexample, reformate gas from the plasma fuel reformer 12 is routedthrough the diverter valve 474 and to a particular emission abatementassembly 400 when the assembly is offline and undergoing a regenerationcycle.

To operate in such a manner, the diverter valve 474 is electricallycoupled to the electronic control unit 16 via a signal line 476. Assuch, the position of the diverter valve 474 is under the control of theelectronic control unit 16. Hence, the electronic control unit 16,amongst its other functions, selectively directs the flow of reformategas from the plasma fuel reformer 12 to either one of the emissionabatement assemblies 400. From there, the flow of reformate gas isfurther routed by the diverter valve 466 so as to direct the flow ofreformate gas from the plasma fuel reformer 12 to the appropriate device(i.e., to either the NO_(X) trap 402 or the soot particulate filter 404)associated with the particular emission abatement assembly 400.

The control scheme executed by the control unit 16 controls the positionof the various diverter valves in order to selectively direct reformategas and exhaust gas to the appropriate device of the combinationemission abatement assemblies 400. In particular, the control unit 16coordinates the position of the reformate gas diverter valves 466 and474 with the position of the exhaust diverter valve 470 to direct theflow of reformate gas and the flow of exhaust gas to the appropriatedevice (i.e., either the NO_(X) trap 402 or the soot particulate filter404) of the appropriate combination emission abatement assembly 400. Inparticular, when the exhaust diverter valve 470 is positioned so as todirect exhaust gas through a particular one of the emission abatementassemblies 400 (i.e., the online assembly 400), the reformate gasdiverter valves 466 and 474 are respectively positioned so as to directthe flow of reformate gas from the plasma fuel reformer 12 to theappropriate device of the offline assembly 400 thereby facilitatingregeneration thereof. As described above, in such a case, the exhaustdiverter valve 470 may be selectively positioned to allow a controlledflow of exhaust gases through the offline assembly 400 if such acontrolled flow is useful during the regeneration process.

Referring now to FIG. 11, there is shown an exhaust gas treatment systemwhich is similar to the system shown in FIG. 10. The same referencenumerals are used in FIG. 11 to designate common components which werepreviously discussed in regard to FIG. 10 with additional discussionthereof being unwarranted.

The system of FIG. 11 is essentially the same as the system of FIG. 10with the exception that a pair of plasma fuel reformers 12 are utilized.The use of multiple fuel reformers is particularly useful in the case ofwhen the reformate gas requirements of the system exceed the productioncapacity of a single reformer.

In the exemplary embodiment shown in FIG. 11, each of the plasma fuelreformers 12 is “dedicated” to one of the assemblies 400. In otherwords, reformate gas from a particular plasma fuel reformer 12 is usedto regenerate one of the NO_(X) traps 402 and one of the sootparticulate filters 404, but is not used in the regeneration of theother trap 402 or filter 404. However, it should be appreciated that tofit the needs of a given system design, the plasma fuel reformers 12 maybe operated to generate and supply reformate gas to any of the devicesassociated with either of the emission abatement assemblies 400. In sucha case, a gas routing/valving scheme and an associated control schememay be designed to allow for such delivery of reformate gas to any ofthe devices of either of the combination emission abatement assemblies400.

As will now be described in greater detail, the plasma fuel reformer 12may be operated in different modes of operation to generate and supplydifferent quantities and/or compositions of reformate gas to differentdevices. In particular, as herein described, a single plasma fuelreformer 12 may be operated to generate and supply reformate gas to anumber of different devices such a fuel cell, a NO_(X) trap, a sootparticulate filter, an intake of an internal combustion engine,etcetera. Although each of these devices may be supplied a commonquantity and/or composition of reformate gas, in certain system designs,it may be desirable to supply one or more such devices with a quantityand/or composition of reformate gas that is different than the quantityand/or composition of reformate gas being supplied to one or more otherdevices.

The quantity of reformate gas produced by the plasma fuel reformer 12during a given period of time may be controlled in a number of differentmanners. For example, the plasma fuel reformer 12 may be selectivelyoperated during the given time period to control the amount of reformategas produced by the reformer. Specifically, one particularly usefulfeature of the plasma fuel reformer 12 is its relatively rapid responseto requests for changes in the production of reformate gas. Indeed, theamount of reformate gas produced by the plasma fuel reformer 12 may bequickly increased or decreased based on amongst other things, the flowrates of the fuel and air being advanced into the reformer and the powerlevel being supplied to the fuel reformer. Moreover, the plasma fuelreformer 12 may also be deacutated for periods of time by interruptingthe power supplied to the electrodes 54, 56 (see FIG. 2) by the powersupply 36 (see FIG. 1). Use of such periods of deactuation may beutilized to control the quantity of reformate gas being generated andsupplied to a particular device during a given period of time.

The quantity of reformate gas being supplied to a particular device mayalso be controlled by controlling the flow of reformate gas to theparticular device irrespective of the quantity of reformate gas beinggenerated by the plasma fuel reformer 12. In particular, the controlscheme for controlling the various reformate gas diverter valvesdescribed herein may be designed to direct a flow of reformate gas to agiven device for a period of time that is different than the period oftime that the valve is positioned to direct the flow of reformate gas toanother device. In other words, the valving scheme utilized to directthe flow of reformate gas to particular devices may be designed tosupply different quantities of reformate gas to different devices.

Likewise, the composition of the reformate gas produced by the plasmafuel reformer 12 may also be controlled in a number of differentmanners. For example, reformate gases of different compositions may beproduced by varying the air-to-fuel ratio of the air/fuel mixture beingprocessed by the plasma fuel reformer 12. Moreover, the location orlocations in which air is introduced into the plasma fuel reformer 12may also vary the composition of the reformate gas being produced. Inparticular, as described above, air may be introduced into the plasmafuel reformer 12 at a number of different locations. For example, air isintroduced into the plasma fuel reformer 12 through the air inlet 74.Air is also introduced into the plasma fuel reformer 12 by mixing thefuel with air prior to injection with the fuel injector 38. Moreover,the plasma fuel reformer 12 may also be embodied to include additionalair inlets. For example, the plasma fuel reformer 12 may be designed toinclude an air inlet for advancing air directly into the reactor chamber50 (i.e., without first being advanced through the plasma-generatingassembly 42). By varying the proportion of the total air flow introducedthrough each of these inlets, the composition of the reformate gas maybe varied.

Operation of the power supply 36 may also be varied to produce varyingreformate gas compositions. For example, by varying the power outputlevel or frequency of the power supply 36, the composition of thereformate gas may be varied.

The composition of the reformate gas may also be varied by varying thepresence, number, or type of catalyst through which the reformate gas isadvanced subsequent to exiting the plasma-generating assembly 42. Forexample, as alluded to above, the plasma fuel reformer 12 may beembodied with or without a catalyst positioned in the reaction chamber50 (i.e., with or without the catalyst 78 of FIG. 2). The reformate gasproduced by a plasma fuel reformer having such a catalyst differs incomposition from the reformate gas produced by a plasma fuel reformerthat does not have such a catalyst. To this end, a plasma fuel reformermay be designed with an internal gas routing/valving scheme thatincludes a bypass flow path for selectively routing the gas exiting theplasma-generating assembly 42 either through the catalyst 78 positionedin the reaction chamber 50 or, alternatively, around such a catalyst.Alternatively, the catalyst may be removed from the reaction chamber andpositioned in a separate housing. In such a case, reformate gas may beselectively routed through such a housing or may bypass such a housingso as to produce reformate gases having different compositions.

It should also be appreciated that additional catalysts may also beutilized to produce reformate gases of varying compositions. Inparticular, irrespective or whether or not a catalyst is positioned inthe reaction chamber 50, a number of additional catalysts may be used totreat the reformate gas. A routing/valving scheme may be designed toselectively route the reformate gas through one or more of suchadditional catalysts so as to produce reformate gases of varyingcompositions.

As described above in regard to FIGS. 1 and 2, the plasma fuel reformer12 may be operated to produce a reformate gas that is rich in, amongstother things, hydrogen and carbon monoxide. The amount of each of thesecompounds in the reformate gas flow may be varied by use in theabove-described manners. Moreover, a flow of reformate gas rich in othercompounds may also be created by the above-described manner. Forexample, reformate gas rich in acetylene, methane, propanol, or ethanolmay also be created.

By varying the quantity and/or composition of the reformate gasgenerated and supplied to a particular device, operation of the devicecan be balanced with fuel reformer efficiency. In particular, operationof the plasma fuel reformer 12 may be configured to generate and supplya quantity and/or composition of reformate gas that is sufficient tosupport operation of the device, without being “wasteful.” Inparticular, the efficiency of the system is correlated to both thequantity of reformate gas produced and the “purity” of the gas. Forexample, the system requires more energy to produce a relatively largequantity of reformate than it does to produce a relatively small amountof reformate gas. Similarly, the system requires more energy to producea reformate gas that has a relatively large amount of hydrogen than onethat has a smaller amount of hydrogen.

From the above description, it should be appreciated that the electroniccontrol unit 16 may be configured to execute a control routine thatallows for “customization” of the quantity and/or composition of thereformate gas being generated and supplied to the various devices. Forexample, in the case of the power systems described in regard to FIGS.3-6, the plasma fuel reformer 12 may be operated to generate and supplya reformate gas to the fuel cell 116 which has a different compositionthan the reformate gas that is generated and supplied to the emissionabatement device 118. Indeed, certain types of fuel cells operate moreefficiently when supplied with a reformate gas that is rich in, forexample, hydrogen. While the emission abatement device 118 may beregenerated with reformate gas rich in hydrogen, regeneration may alsobe sustained with a reformate gas that has not been reformed to such adegree. In particular, regeneration of the emission abatement device 118may be sustained with a reformate gas rich in hydrocarbons that arelarger than hydrogen. For example, regeneration of the emissionabatement device may be sustained by use of a reformate gas havingsufficient amounts of acetylene, methane, propanol, or ethanol. Hence,the plasma fuel reformer 12 may be operated in one mode of operation inwhich hydrogen-rich reformate gas is generated and supplied to the fuelcell 116, and also a different mode of operation in which reformate gasrich in larger hydrocarbons is generated and supplied to the emissionabatement device 118.

As alluded to above in regard to the discussion relating to FIGS. 3-6,reformate gas from the plasma fuel reformer 12 may also be supplied tothe intake of the internal combustion engine 112. In such a case, thequantity and/or composition of the reformate gas supplied to the engine112 may differ from the quantity and/or composition of the reformate gassupplied to another device (e.g., the fuel cell 116).

A similar scheme may be utilized during regeneration of the combinationemission abatement assembly 400 of FIGS. 8-11. In particular, in certaindesigns, it may be desirable to generate and supply hydrogen-richreformate gas to one of the devices (e.g., the NO_(X) trap 402 or thesoot particulate filter 404), while generating and supplying reformategas rich in larger hydrocarbons to the other device. For example, theplasma fuel reformer 12 may be operated in one mode of operation inwhich hydrogen-rich reformate gas is generated and supplied to theNO_(X) trap 402, and also a different mode of operation in whichreformate gas rich in larger hydrocarbons is generated and supplied tothe soot particulate filter 404, or visa versa.

A control scheme that varies the quantity of reformate gas delivered toeach device may also be utilized during regeneration of the combinationemission abatement assembly 400. In particular, it may be desirable togenerate and supply to one of the devices (e.g., the NO_(X) trap 402 orthe soot particulate filter 404) a quantity of reformate gas that isdifferent from the quantity of reformate gas delivered to the otherdevice. For example, the plasma fuel reformer 12 may be operated in onemode of operation in which a first quantity of reformate gas isgenerated and supplied to the NO_(X) trap 402, and also a different modeof operation in which a second, smaller quantity of reformate gas richis generated and supplied to the soot particulate filter 404, or visaversa.

As can be seen from the foregoing description, the concepts of thepresent disclosure provide numerous features and advantages relative toother systems. For example, amongst other things, the concepts of thepresent disclosure allow for the operation of a heating and airconditioning system of an on-highway truck without requiring concurrentoperation of the truck's engine. Such a feature is advantageous for bothfuel consumption and emissions reduction reasons.

Moreover, by generating and supplying reformate gas to the emissionabatement devices of the present disclosure, the efficiency of suchdevices is enhanced. In addition, the number and type of compounds whichmay be treated is also enhanced.

In addition, by use of a combination emission abatement assembly, the asingle fuel reformer may be utilized to regenerate a number of differentexhaust treatment devices. In such a way, multiple exhaust compounds(e.g., NO_(X) and soot) can be removed from the exhaust flow by use of asingle assembly.

Further, by “customizing” the quantity and/or composition of reformategas generated and supplied to various devices, the efficiency associatedwith operation of the plasma fuel reformer 12 is enhanced. In otherwords, operation of the plasma fuel reformer 12 may be refined togenerate and supply a quantity and/or composition of reformate gas thatis sufficient to support operation of a given device, without being“wasteful.”

While the disclosure is susceptible to various modifications andalternative forms, specific exemplary embodiments thereof have beenshown by way of example in the drawings and has herein be described indetail. It should be understood, however, that there is no intent tolimit the disclosure to the particular forms disclosed, but on thecontrary, the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the disclosure.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the apparatus, systems, and methodsdescribed herein. It will be noted that alternative embodiments of theapparatus, systems, and methods of the present disclosure may notinclude all of the features described yet still benefit from at leastsome of the advantages of such features. Those of ordinary skill in theart may readily devise their own implementations of apparatus, systems,and methods that incorporate one or more of the features of the presentdisclosure and fall within the spirit and scope of the presentdisclosure.

For example, although the emission abatement devices described herein(e.g., the emission abatement device 300) are described as receivingreformate gas containing hydrogen from a fuel reformer, it should beappreciated that the source of hydrogen gas may be embodied as a numberof different types of devices. For example, the source of hydrogen gasmay be embodied as tank of hydrogen gas (i.e., “bottled” hydrogen gas).Alternatively, the source of hydrogen gas may be embodied as a hydrogengenerator that generates hydrogen from other compounds. One example of ahydrogen generator is a device that produces hydrogen gas viaelectrolysis.

1. An apparatus for removing particulate soot from an exhaust gas of aninternal combustion engine, comprising: a source of hydrogen gas, acatalyst configured to catalyze an exothermic oxidation reaction betweenthe hydrogen gas and a gaseous component comprising oxygen, and a sootfilter positioned downstream from the catalyst, wherein heat generatedby the exothermic oxidation reaction is transferred to the soot filter.2. The apparatus of claim 1, further comprising a housing, wherein thecatalyst and the soot filter are housed in the housing.
 3. The apparatusof claim 1, wherein the source of hydrogen gas comprises a fuelreformer.
 4. The apparatus of claim 3, wherein the fuel reformer isconfigured to reform hydrocarbon fuel into a reformate gas containinghydrogen gas.
 5. The apparatus of claim 3, wherein the fuel reformercomprises a plasma fuel reformer.
 6. The apparatus of claim 1, whereinthe soot filter has a catalytic material disposed thereon.
 7. A methodof regenerating a soot filter comprising the steps of: advancinghydrogen gas and an exhaust gas of an internal combustion engine intocontact with a catalyst, generating heat from a reaction between thehydrogen gas and the exhaust gas in the presence of the catalyst, andtransferring the heat downstream to the soot filter to ignite soottrapped in the soot filter.
 8. The method of claim 7, further comprisingthe step of reforming a hydrocarbon fuel to produce the hydrogen gas. 9.The method of claim 8, wherein the reforming step comprises operating afuel reformer to reform the hydrocarbon fuel to produce a reformate gascontaining the hydrogen gas.
 10. A method of regenerating a particulatecarbon-based soot filter of a diesel engine, the method comprising thesteps of: operating a fuel reformer to produce a reformate gas,advancing the reformate gas and an exhaust gas from the diesel enginethrough an oxidation catalyst to generate an exothermic reaction, andheating the soot filter with heat from the exothermic reaction to asufficient temperature to ignite soot particulates trapped in the sootfilter which is positioned downstream from the catalyst.
 11. The methodof claim 10, wherein the operating step comprises operating a plasmafuel reformer.
 12. The method of claim 10, wherein the operating stepcomprises operating the fuel reformer to produce the reformate gas froma hydrocarbon fuel.
 13. The method of claim 10, wherein the operatingstep comprises operating the fuel reformer to produce the reformate gasfrom a diesel fuel.
 14. An emission abatement assembly, comprising: afuel reformer configured to reform hydrocarbon fuel into a reformategas, a catalyst configured to catalyze an exothermic oxidation reactionbetween the reformate gas and a gaseous component comprising oxygen, anda soot filter positioned downstream of the catalyst, wherein heatgenerated by the exothermic oxidation reaction is transferred to thesoot filter.
 15. The assembly of claim 14, further comprising a housinghaving a reformate gas inlet, wherein: the fuel reformer is fluidlycoupled to the reformate gas inlet, and the catalyst and the soot filterare housed in the housing.
 16. The assembly of claim 14, wherein thesoot filter has a catalytic material disposed thereon.
 17. The assemblyof claim 14, wherein the fuel reformer comprises a plasma fuel reformer.